COVERT, MI — The Nuclear Regulatory Commission has sent an additional inspector to Palisades nuclear power plant as crews look to repair a leak in the plant. The inspector is a materials specialist who will observe workers as they fix the primary coolant system in the containment building.

“This is a concern for the NRC,” said Prema Chandrathil, a spokeswoman for the agency. Federal regulators are“watching w hat the plant does closely," she said.

As of Tuesday morning, work continued at the plant in Covert, just north of South Haven. Entergy spokesman Mark Savage wrote in an e-mail that work at the plant currently involves "schedule development, planning, and training activities in preparation for repair work."

The leak has been ongoing for some time: the NRC knew about it since July 10, Chandrathil said. According to federal regulations, the NRC would have shut down the plant if the unidentified leak was more than one gallon an hour. The plant has a self-imposed limit that it would shut down if the leak reached 0.5 gallons an hour. When plant managers decided to shut down, the leak was at 0.3 gallons an hour.

“Cooling down the reactor allows the plant’s staff to inspect and look in areas they may not be able to during operation,” Chandrathil said.

Once the plant started reducing power, workers could look at parts of the pipe to see where the problem may be located, Chandrathil said. Since a plant crew found the cause of the leak, the plant had to be shut down, since federal regulation says a leak which has a known cause should be repaired.

The NRC inspector sent to the plant is in addition to the two regularly stationed at Palisades. The additional inspector will look at what crews are doing and how they repair the leak, Chandrathil said, as well as looking into the cause of the leak.